Disruption of electric arcs



J. F. TRITLE.

DISRUPTION 0F ELECTRIC'ARCS.

APPLICATION FlLED DEC. 4, 1919.

1,39 ,981, Patented Dec. 6, 1921,

Fig.3.

Insulation Switch Contact Inventor: John F. Tritl e,

His flctor-nen UNITED STATES PATENT OFFICE.

JOHN IE. TRITLE, OF SCHENECTADY, NEW YORK, ASSIGNOR 'lJO' GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK. I

DISRUPTION 0F ELECTRIC ARCS.

Specification of Letters Patent.

IZatented Dec. 6, 192i.

Application filed December 4, 1919. Serial No. 342,326.

My invention relates to disruption of elec- ,tric arcs and it providesan improved method and improved means whereby the are formed betweenarcing electrodes is quickly disrupted.

Although not necessarily limited thereto, my invention has a particularapplication -in the disruption of the arcs formed between cooperatingcircuit interrupting contacts of electric switches.

In one of its aspects,.my invention comprises an arrangement whereby thearc is caused to be formed in a confined space and to proceed directlyfrom the arcing electrodes or the switch contacts in the same plane inwhich the arc lengthens, or a plane parallel thereto, through a chutewhich is narrower at its exit than at the space in which the arc isformed, thereby increasing the resistance and thecooling surface of theare for a given length of are by decreasing its cross-section.

. chute will be narrower than the arcing electrodesor the switchcontacts at Which the arc is formed. Furthermore, when a. magneticblowout is used in connection with the arc chute, the arc stream iscaused to be practically perpendicular to the lines of force of theblowout.

In another of its aspects, my invention comprises the method whereby thearc is split longitudinally into a plurality of multiple connectedparts. It has heretofore been proposed to lengthen the arc byinterposing barriers which are transverse to the plane in which the arclengthens in order to increase the length of the are or; split up thearc into a plurality of'smaller arcs in series relation so that it willbe disrupted quickly. However, such schemes have the disadvantage,particularly where the arc is formed on a relatively high potentialcircuit, that a great difference of'potential exists between the partsof the are on oppo site sides ofthe barrier and the insulation betweenthose parts of the are is required to be considerable or the partsofthe' arc'will The exit of the arc goin, thereby defeating the objectof the arriers. VVlth my method, since the arc is split into a pluralityof multiple parts there i is practically no difference of potentialbetween the parts of the arc; and the potential stress on the meanswhich causes the arc to be formed into a plurality of parts is thereforevery small, if any.

My invention, further, comprises an arrangement of apparatus whereby myimproved method is-ca-rried into effect, and in one of its aspects abarrier of insulating material is disposed in the plane in which the arewould ordinarily lengthen, or in a plane parallel thereto, or in theplane of movement of the switch contacts, whereby the arc is, split uplongitudinally into a plurality of multiple connected parts betweenwhich there is ubstantially no difference of potential, so that thepotentialstress on the barrier is therefore very small, if any.

In certain other of its aspects, my invention comprises an arrangementhaving in combination the feature of causing the arc to be formed in aconfined space and to proceed directly from the switch contacts in theplane in which the arc lengthens or a plane parallel thereto through achute which is narrower at its exit than at thespace in which the arc isformed, and the feature of splitting the are into a plurality ofmultiple parts which are substantially parallel to the plane in whichthe arc would ordinarily lengthen.

My invention also comprise the method of causing the arc to be split upinto a plurality of multiple connected parts and causing thecross-section of the parts to be reduced.

For a better understanding of my invention reference is had to theaccompanying drawings, wherein Figure 1 shows a drum type controllerprovided with barriers to form are chutes in accordance with myinvention; Fig. 2 is a section of the controller shown in Fig. 1 talgenon the line 2-2; Fig. 3 is a simplified diagrammatic View for thepurpose of showing how the arc is caused to proceed from the switchcontact in the plane of movement of the switch contacts through apassage having a narrow exit; Fig. 4 is a top view of one of thebarriers constructed in accordance with my inventhe part designatedswitch contact is one of a pair of circuit interrupting contacts, andthe two cooperating barriers, one of which is designated insulation, aredisposed adjacent the contacts so that the arc formed between thecontacts is blown out throughthe chute formed between the barriers. Eachof the barriers is so constructed that when assembled as shown, the arebetween the contacts is formed in a space. which is larger than theexit. The exit of constricted area -is located so as to be in the planein which the arc would ordinarily expand, preferably in the same planeas the center line of the circuit interrupting contacts and in the planeof movement of the contacts. The greater part of the arc chute isnarrower than the contacts, so thatwhen the arc is formed it will blowout through the arc chute as shown in the dotted lines whichare-intended to show successive sections of the are as the arclengthens. The arc will be gradually confined between the facesofthe'barriers, so that when the arc reaches the narrow exit it is verygreatly confined, its cross-section is less, its resistance and coolingeffect are greater, and it will therefore disrupt itself very quickly.In this figure the force which causes the arc to proceed in thedirection indicated is the heat ofthe arc, but, as will be laterexplained, the arc is caused to proceed in any direction desired bymeans of a magnetic blow-out' I am at present unable to state positivelythe theory upon which this action of quickly disrupting the arc isbased, but repeated tests and comparisons with are chutes constructed inaccordance with well known practice have shown the practicaleffectiveness of my invention, whatever may be the theory upon which itis based. It would appear, however, that the action is caused byincreasing the resistance and cooling effect of the are by decreasingits cross-section. r

Referring now to Figs. 1 and 2, the controller shaft 18 has mountedthereon and insulated therefrom a. plurality of metallic segments, ofwhich the segment 19 is a part. Cooperating with the segment 19 is'astationary .circuit making contact 20 which, to-

gether with the segment 19, forms a part of an electric circuitcompleted and interrupted by the controller. From Fig. 1 it will be seenthat there area plurality of these metallic segments and cotiperatingcontacts arranged serially along the shaft 18,'this in itself being awellknown construction. The shaft 18 with the metallic segments thereonis rotated by means of a handle 21 throughout the successive positionsfor controlling an electric circuit, for starting motors, and the like.In a plane parallel to the plane of movement of the segment 19 and thestationary contact 20.is a barrier 22 of noninflammable heat resistingmaterial, such as a hard fiber, an asbestos composition, or the like.This barrier is illustrated in more detail in Figs. 4 to 7 inclusive. Itis constructed with a cutaway portion 23 on each of its fiat sidesformed by beveling out a portion of each fiat side so that at themeeting of the two beveled surfaces a comparatively sharp edge is formedalong part of the middle of the barrier, as shown in Figs. 5, 6 and 7.

On one end of the barrier a foot 24 is formed,

and on the other end a foot 25 is formed,

so that when the barriers areassembledas shown at 26, 27 and 28 in Fig.1, the feet determine the spaces between adjacent bar-, The barriers aredisposed with respect to the circuit interrupting contacts in riers.

a plane parallel to the plane of movement of the contacts, preferablywith the sharp edge formed by the meeting of the two beveled surfaces ata point opposite the middle of the contacts as shown in Figs. 8, 9 and10. In Fig. 8 the barriers 29 and 30 are equidistantly disposed onopposite sides of the segment 31, and the barrier 32 of a form similarto the barrier 22 shown in Figs. 4 and 7 inelusive has the sharp edge ofits cutaway portion disposed in a plane substantially parallel toplaneof movement of the circuit interrupting contacts along the centerline of the contacts, of which the segment 31 forms a part. In thebarriers 29 and '30 metallic plates 33 and 34 respectively of magneticmaterial are embedded,- these plates forming part of a magnetic blowoutdevice.

For purposes of illustration, dotted lines are shown, illustrating asection of the arc andsections of the parts of the arc in order toillustrate the manner in which'the are formed between the switchcontacts is split up into two parts which are substantially parallel tothe plane of movement of the contacts,

equidistantly disposed from the center line of the contacts andparallelto the plane in and'each of the substantially parallel parts of the arcis substantially perpendicular to the lines of force of the magneticblowout. The are will be caused to be disrupted quickly because of beingsplit up into a plurality of parts, because each part is reduced incross-section, and by reason of the a fact that the arcstream is soconfined and directed that a large portion of the lines of force of theblowout are effective in rupturing the arc. In other words, the arcstream is prevented from wandering from one side of the wide chute tothe other in such a way that part of the arc stream is parallel to thelines of force of the blowout and thus defeat the purpose of the blowoutand make it difficult generally to disrupt the arc. Ordinarily the arcwill be split up into parts, but the extent to which the parts lengthenwill not be the same. One part will ordinarily be smaller and bedisrupted quickly so that the final disruption of the arc occurs in theother arc chute. However, when very heavy currents are broken the arcmay lengthen substantially equally in each arc chute.

In Fig. 9 I have shown an arrangement in which two circuit interruptingsegments 35 and 86 are connected in multiple for opening an electriccircuit, and the barriers 37 and 38 are equidistantly' disposed onopposite sides of the contacts. The barrier 39, having the sharp edgeformed by the meeting of the two cutaway portions is disposed oppositethe center line of the segment 35. A barrier 40 of similar constructionis also disposed in a similar way opposite the contact 36. Three arechutes having narrow exits are thus formed, and the arcs formed at thecontacts ,7 35 and'36 are split up and reduced in cross- 40 section ina'manner similar to that explained in connection with Fig. 8, andlikewise quickly disrupted. It will be understood that since thesegments 35 and 36 are electrically connected, if the mechanicalconstruction of these segments and their cooperating contacts is perfectthe arc will be broken at both segments simultaneously. However, inpractice such perfection is ordinarily not obtained and the arc will beformed at either one of the segments. When a normal current is beingbroken with the are formed at segment 35, for instance, the arc willproceed out through either the upper or the middle chute, but if a veryheavy current is broken the arc will be split up, part going'out throughea'chof the upper and middle chutes, or a part out each of the threechutes. In Fig, 10 the are formed between the contact finger 20 and thecontact segment 19 is shown as being split in a line substantiallyparallel to plane of movement of the switch contacts opposite the centerline of the contacts and in the plane in which the arc would ordinarilyexpand, the lower part of the are not being shown since it is covered bythe barrier 22. A blowout coil 41 of the usual construction is alsoshown, and it will be understood that a part of the blowout device isembedded in the lower barrier 42 and a part in the upper barrier ofsimilar construction which has been re moved in order to show the mannerin which the barrier 22'splits the arc. It will be understood that thelower part of the arc will be blown out through the narrow exit 43 ofthe arc chute, and that the upper part of the arc will be blown outthrough the narrow exit of the arc chute formed between the barrier 22and the upper barrier, which has been removed for purposes ofillustration.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.

What I claim' as new and desire to secure by Letters Patent of theUnited States, is:

1. In an electric switch, a pair of relatively movable cooperatingcircuit interrupting contacts between which an arc is formed when thecontacts separate, and an arc chute having a comparatively long narrowexit with the long axis of the exit disposed in the planeof movement ofsaid contacts for reducing the cross-section of the arc.

2. In an electric switch, an arc chute having apassage for the are whichforms between the switch contacts, the said passage disposed in a planesubstantially parallel to the plane in which the arc lengthens andnarrower in the direction transverse to the direction in which the arclengthens than the widthof the switch contacts.

3. Means for interrupting an electric circuit comprising a pair ofrelatively movable circuit interrupting contacts between which an arc isformed when the contacts separate, and means for causing the arc toproceed through a passage in the plane of movement of the switchcontacts, the said passage having an exit narrower than the width of theswitch contacts.

it. The combination in an electric switch of a pair of relativelymovable cooperatin 'an arc is formed when the contacts separate,

a barrier on each side of the switch contacts,

the interior surfaces of the barriers forming an arc chute which issubstantially parallel to the plane of movement of the switch contactsand which is narrower for a part of its length than the space in whichthe arc is formed:

6. The combination in an electric switch of a pair of relatively movablecooperating circuit interrupting contacts between which an arc is formedwhen the contacts separate, a barrier on each side ,of the switchcontacts, the interior surfaces of the barriers forming an arc chutewhich is parallel to the plane of movement of the switch contacts andwhich is narrower for the greater part of its length than the width ofthe switch contacts.

7. The combination in an electric switch of a pair of relatively movablecooperating circuit interrupting contacts between which an arc is formedwhen the contacts separate, and means for causing the are formed betweenthe contacts to proceed through a passage which is narrower for thegreater part of its length than the width of the circuit interruptingcontacts and which is disposed in a plane substantially parallel to theplane of movement of the switch contacts.

8. The combination in an electric switch of a pair of cooperatingcircuit interrupting contacts between which an arc isformed when thecontacts separate,a barrier on each side of the switch contacts, theinterior surfaces of the barriers forming a flat arc chute which is inthe plane of movement of the said contacts and which is narrower for thegreater part of its length than the width of the switch contacts, and amagnetic blow-out arranged so that the lines of force of the blow-outare substantiallv perpendicular to the path of the arc current.

9. The combination of a pair of arcing electrodes between which anarc isformed, and means for splittingthe are into a plurality of multipleconnected parts.

10. The combination in an electric switch of a pair of cotiperatingcircuit interrupting contacts between which an arc is formed when thecontacts separate, and means disposed in the path of the are oppositethe contacts for splitting the are into a plurality of pailrts having amultiple relation to I each ot er.

11. The combination in an electric switch of a pair of cooperatingcircuit interruptin contacts between which an arc is forme 1 when'thecontacts separate,and means for splitting the arc longitudinally into aplurality of parts and causing the parts to pro-' ceed throughsubstantially parallel passages. 12. The combination in an electricswitch of a pair of cooperating circuit interrupting contacts betweenwhich an arc is formed when the contacts separate, and means forsplitting the are into a plurality of parts having a multiple relationto each other and are, each of the passages being substantially parallelto the plane in which the arc would ordinarily lengthen.

13. The combination with'a pair of arcing electrodes between which anarc is formed, and means for splitting the arc longitudinally into aplurality of parts, and reducing the cross-section of each part.

14:. The combination in an electric switch of a pair of cooperatingcircuit interrupting contacts between which an arc is formed when thecontacts separate, and means for splitting the are into a plurality ofparts having a multiple relation to each other and causing each part topass through a restricted passage which reduces the thickness of thepart.

15. The combination in an electric switch of a pair of cooperatingcircuit interrupting contacts between which an arc is formed when thecontacts separate, and means disposed in the plane in which the arclengthens for splitting the are into a plurality of multiple connectedparts.

16. The combination in an electric switch of a air of relatively movablecooperating circuit interrupting contacts between which an arc is formedwhen the contacts separate,

and means disposed in the plane ofmovement of the switch contactsandprojecting into the path of the are for dividing the arc into aplurality of parts having a multiple relation to each other.

17. The combination in an electric switch of a pair of relativelymovable coiiperating circuit interrupting contacts between which an arcis formed when the contacts separate, means disposed in the plane ofmovement of the switch contacts opposite the middle of 1 said contactsfor splitting the are formed between the contacts into a plurality ofparts,

and means for causing the said parts to proceed from the contactsparallel to each other in the plane of movement ofthe switch contacts.

of a air of relatively movable circuit interrupting contacts betweenwhich an arc is formed when the contacts separate, and means forsplitting the are into two parts comprising a flat'barrier dis osedtheplane of movement of the switch contacts,

the said barrier having a beveled surface on each flat side, the meetingof the two beveled 18. The combinationin an electric switch surfacesforming a comparatively sharp edge opposite the middleof the switchcontacts.

19. The combination in an electricswitch of a pair of coiiperatincircuit interrupting contacts between wh1c an arc is formed when thecontacts separate, means for dividthe plane of movement of the switchcontacts opposite the middle of said contacts and a barrier disposed oneach side of the first mentioned barrier for splitting the arc into aplurality of parts and causing each part to lengthen in a passage havingan exit narrower than the width of the switch contacts in a planesubstantially parallel to the of movement of theswit-ch contacts.

'21. The combination in an electric switch of a pair of relativelymovable cooperating circuit interrupting contacts, between which an arcis formed when the contacts separate, means comprising a barrierdisposed in the plane of movementof the switch contacts opposite themiddle of said contacts; a barrier disposed on each side of the firstmentioned barrier and a magnetic blow-out device arranged so that thelines of force of the blowout are substantially perpendicular to thepassages between the said barriers, for disrupting the are formedbetween the contacts by splitting the are into a plurality of parts andcausing each part to lengthen in a assage having an exit narrower thanthe wldth of the switch contacts in a plane substantially parallel tothe plane of movementof the switch contacts.

22. The method of disrupting an arc which consists in splitting the areinto a plurality of multiple connected parts.

plane cross section of the parts as the parts lengthen.

24. The methodv of disrupting an arc formed between a pair of relativelymovable cooperating circuit interrupting contacts which consists insplitting the arc into a plurality of multiple connected parts in theplane of movement of the contacts, causing each part of the arc to belengthened in the plane of movement of the contacts, and causing thecross section of each part of the arc to be decreased as the partslengthen.

25. The method of disrupting an arc which consists in reducing thecross-section of the arc and splitting it into a plurality of multipleconnected p rts.

26. The method of disrupting an are which consists in splitting the areinto a plurality of multiple connected parts, and causing thecross-section of each part to be reduced.

27. The method of disrupting an are which consists of splitting the arcinto a plurality of multiple connected parts, causing each part to bemagnetically lengthened in a plane substantially parallel to the planein which the arc would ordinarily lengthen, and causing thecross-section of each duced as it lengthens.

In witness whereof, I have hereunto set my hand this 2nd day ofDecember, 1919.

JOHN F. TRITLE.

part to be re-

